Worm Dissection

Class Specimen Determination

Nematodes

• Roundworm (Ascaris)

Annelida

• Sandworm (Nereis)
• Earthworm (Lumbricus)
• Leech (Haemopis)
• Amphitrite

Platyhelminthes

• Liver Fluke (Fasciola Hepatica)
• Dog Tapeworm (Dipylidium)
• Tapeworm (Moniezia)
• Flatworm (Planaria)
• Taenia (Saginata, sp)

3 Species Examples

Red Worms (Eisenia fetida)

Marine Flatworm (Pseudocero biforcus)

3 Annelid Species:

1. Earthworms (Lumbricus terrestris)

• There are 2,700 different kinds of earthworms
• A worm has no arms, legs, or eyes
• Baby worms hatch from cocoons smaller than a grain of rice
• When the worm's skin dries out, it will die
• Worms tunnel deep and bring subsoil closer to the surface which mixes with topsoil

2. Ragworms (Hediste diversicolor)

• They can live for 1-3 years depending on how fast they mature
• Found on muddy shorelines and live in burrows
• They are important prey to at least 15 bird species and also used as bait
• They reach about 2-4 inches in length
• Common throughout north-west Europe; along Atlantic coasts

3. Red Worms (Eisenia fetida)

• Live in the top 12 inches of soil
• Feed on organic decaying matter
• The two most common uses for red worms are for composting and fish bait
• Also called wiggler worms
• Can convert organic material to natural fertilizer

3 Nematoda Species:

1. Guinea Worm Female (Dracunculus medinensis)

• Found beneath the skin of the legs of mammals in North America
• Female worms can reach up to 28cm in length
• Can cause Guinea worm diseases which is caused by the female that emerges painfully from a mammals skin on their legs
• This disease is caused by drinking water usually from ponds
• This disease is also known as Dracunculiasis

2. Old World Hookworm (Ancylostoma duodenale)

• Found in the small intestines of humans, dogs, and cats
• Eggs are passed into the feces of the host
• Female can lay beteen 10,000 and 30,000 eggs per day
• Causes malnutrition from protein and iron deficiency
• 1.28 billion people are affected by this parasite

3. Whipworms (Trichuris trichiura)

• Parasites that cause a disease called Trichuriasis, an intestinal disease
• Found in the intestines of animals and humans
• Live in warm, humid climates
• Animals can acquire the disease by orally ingesting worm eggs found in the environment
• Humans can contract the disease by drinking contaminated water or ingesting soil containing the infected feces

3 Platyhelminthes Species:

1. Flatworms (Schistosoma mansoni)

• Parasitic (especially to humans) worms that cause intestinal schistosomiasis
• Fond of living in organs, intestinal tract, and liver
• Has infected 83.3 million people worldwide
• Lays eggs within it's host and reproduction begins
• 1.2 to 1.6 cm long by 0.016 cm wide
  

2. Marine Flatworms (Pseudocero biforcus)

• Blue lavender color with a white stripe down the middle of their body
• Found along external reef slopes
• Found in the Western Pacific
• They feed on colonial ascidians
• Approximately 6cm in length

3. Planarians (Planariidae)

• Free-living flatworm that are found in freshwater
• They don't have teeth
• They are carnivores
• Most Planarians are less than 1cm long
• Soft bodied and generally leaf-shaped

Major Classes

(3) Major Classes of Annelids:

1. Class Oligochaeta - earthworms

2. Class Hirudinea - leeches

3. Class Polychaete - marine worms

(3) Major Classes of Platyhelminthes

1. Class Turbellaria - free-living flatworms

2. Class Trematoda - flukes

3. Class Cestoda - tapeworms

(2) Major Classes of Nematodes

1. Adenophorea

2. Secernentea

Research Article Summary

Annelida is a phylum of soft bilaterally symmetrical worms. 12,000 species of Annelida is grouped into three classes: the oligochaetes [earthworms and freshwater worms], hirudineans [leeches], and the polychaetes [marine worms]. You can find these segmented worms in mud, sand, and rock crevices and among many other things even a sponge. The body of an annelid consists of a head, a trunk, and a section of the body called a pygidium which is unsegmented. Their body wall consists of muscles that assist the annelid in crawling and swimming. They also possess short bristles called setae that are used to grip the soil to hold the animal in the tube and/or assist it in swimming.

The annelids digest through a single gut that runs through the middle of their body and is separated from their body wall by coelom which is the worm’s body cavity. The body cavity works as a skeleton in the annelids except for the leeches. The annelid’s muscles depend on the fluid found in their body cavity to function properly. Reproduction in annelids is either sexual or asexual. In most annelids, respiration occurs directly through their body wall because they have no special organs for gas exchange. However some aquatic annelids have gills used for respiration. The nervous system of an annelid consists of a brain which is connected by nerves to a nerve cord that runs throughout their body. The sense organs of annelids include eyes, taste buds, tentacles, and equilibrium organs. Circulation throughout the annelids body occurs through the containment of a red-oxygen carrying pigment, a green-oxygen carrying pigment, or some have unpigmented blood. The system is usually confined within blood vessels or the system is found partially open in some annelids such as the leeches.

Platyhelmenthes, nematoda, and annelid videos

Annelid video - http://www.youtube.com/watch?v=eDjhM3TsOnQ
Platyhelmenthes - http://www.youtube.com/watch?v=nwtm5nW_a2Q
Nematodes video - http://www.youtube.com/watch?v=X1YiIiPUQR8